net/decnet/dn_route.c

   1 /*
   2  * DECnet       An implementation of the DECnet protocol suite for the LINUX
   3  *              operating system.  DECnet is implemented using the  BSD Socket
   4  *              interface as the means of communication with the user level.
   5  *
   6  *              DECnet Routing Functions (Endnode and Router)
   7  *
   8  * Authors:     Steve Whitehouse <SteveW@ACM.org>
   9  *              Eduardo Marcelo Serrat <emserrat@geocities.com>
  10  *
  11  * Changes:
  12  *              Steve Whitehouse : Fixes to allow "intra-ethernet" and
  13  *                                 "return-to-sender" bits on outgoing
  14  *                                 packets.
  15  *              Steve Whitehouse : Timeouts for cached routes.
  16  *              Steve Whitehouse : Use dst cache for input routes too.
  17  *              Steve Whitehouse : Fixed error values in dn_send_skb.
  18  *              Steve Whitehouse : Rework routing functions to better fit
  19  *                                 DECnet routing design
  20  *              Alexey Kuznetsov : New SMP locking
  21  *              Steve Whitehouse : More SMP locking changes & dn_cache_dump()
  22  *              Steve Whitehouse : Prerouting NF hook, now really is prerouting.
  23  *                                 Fixed possible skb leak in rtnetlink funcs.
  24  *              Steve Whitehouse : Dave Miller's dynamic hash table sizing and
  25  *                                 Alexey Kuznetsov's finer grained locking
  26  *                                 from ipv4/route.c.
  27  *              Steve Whitehouse : Routing is now starting to look like a
  28  *                                 sensible set of code now, mainly due to
  29  *                                 my copying the IPv4 routing code. The
  30  *                                 hooks here are modified and will continue
  31  *                                 to evolve for a while.
  32  *              Steve Whitehouse : Real SMP at last :-) Also new netfilter
  33  *                                 stuff. Look out raw sockets your days
  34  *                                 are numbered!
  35  *              Steve Whitehouse : Added return-to-sender functions. Added
  36  *                                 backlog congestion level return codes.
  37  *              Steve Whitehouse : Fixed bug where routes were set up with
  38  *                                 no ref count on net devices.
  39  *              Steve Whitehouse : RCU for the route cache
  40  *              Steve Whitehouse : Preparations for the flow cache
  41  *              Steve Whitehouse : Prepare for nonlinear skbs
  42  */
  43
  44 /******************************************************************************
  45     (c) 1995-1998 E.M. Serrat           emserrat@geocities.com
  46
  47     This program is free software; you can redistribute it and/or modify
  48     it under the terms of the GNU General Public License as published by
  49     the Free Software Foundation; either version 2 of the License, or
  50     any later version.
  51
  52     This program is distributed in the hope that it will be useful,
  53     but WITHOUT ANY WARRANTY; without even the implied warranty of
  54     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  55     GNU General Public License for more details.
  56 *******************************************************************************/
  57
  58 #include <linux/errno.h>
  59 #include <linux/types.h>
  60 #include <linux/socket.h>
  61 #include <linux/in.h>
  62 #include <linux/kernel.h>
  63 #include <linux/sockios.h>
  64 #include <linux/net.h>
  65 #include <linux/netdevice.h>
  66 #include <linux/inet.h>
  67 #include <linux/route.h>
  68 #include <linux/in_route.h>
  69 #include <net/sock.h>
  70 #include <linux/mm.h>
  71 #include <linux/proc_fs.h>
  72 #include <linux/seq_file.h>
  73 #include <linux/init.h>
  74 #include <linux/rtnetlink.h>
  75 #include <linux/string.h>
  76 #include <linux/netfilter_decnet.h>
  77 #include <linux/rcupdate.h>
  78 #include <linux/times.h>
  79 #include <asm/errno.h>
  80 #include <net/neighbour.h>
  81 #include <net/dst.h>
  82 #include <net/flow.h>
  83 #include <net/dn.h>
  84 #include <net/dn_dev.h>
  85 #include <net/dn_nsp.h>
  86 #include <net/dn_route.h>
  87 #include <net/dn_neigh.h>
  88 #include <net/dn_fib.h>
  89
  90 struct dn_rt_hash_bucket
  91 {
  92         struct dn_route *chain;
  93         spinlock_t lock;
  94 } __attribute__((__aligned__(8)));
  95
  96 extern struct neigh_table dn_neigh_table;
  97
  98
  99 static unsigned char dn_hiord_addr[6] = {0xAA,0x00,0x04,0x00,0x00,0x00};
 100
 101 static const int dn_rt_min_delay = 2 * HZ;
 102 static const int dn_rt_max_delay = 10 * HZ;
 103 static const int dn_rt_mtu_expires = 10 * 60 * HZ;
 104
 105 static unsigned long dn_rt_deadline;
 106
 107 static int dn_dst_gc(void);
 108 static struct dst_entry *dn_dst_check(struct dst_entry *, __u32);
 109 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *);
 110 static void dn_dst_link_failure(struct sk_buff *);
 111 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu);
 112 static int dn_route_input(struct sk_buff *);
 113 static void dn_run_flush(unsigned long dummy);
 114
 115 static struct dn_rt_hash_bucket *dn_rt_hash_table;
 116 static unsigned dn_rt_hash_mask;
 117
 118 static struct timer_list dn_route_timer;
 119 static DEFINE_TIMER(dn_rt_flush_timer, dn_run_flush, 0, 0);
 120 int decnet_dst_gc_interval = 2;
 121
 122 static struct dst_ops dn_dst_ops = {
 123         .family =               PF_DECnet,
 124         .protocol =             __constant_htons(ETH_P_DNA_RT),
 125         .gc_thresh =            128,
 126         .gc =                   dn_dst_gc,
 127         .check =                dn_dst_check,
 128         .negative_advice =      dn_dst_negative_advice,
 129         .link_failure =         dn_dst_link_failure,
 130         .update_pmtu =          dn_dst_update_pmtu,
 131         .entry_size =           sizeof(struct dn_route),
 132         .entries =              ATOMIC_INIT(0),
 133 };
 134
 135 static __inline__ unsigned dn_hash(__le16 src, __le16 dst)
 136 {
 137         __u16 tmp = (__u16 __force)(src ^ dst);
 138         tmp ^= (tmp >> 3);
 139         tmp ^= (tmp >> 5);
 140         tmp ^= (tmp >> 10);
 141         return dn_rt_hash_mask & (unsigned)tmp;
 142 }
 143
 144 static inline void dnrt_free(struct dn_route *rt)
 145 {
 146         call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
 147 }
 148
 149 static inline void dnrt_drop(struct dn_route *rt)
 150 {
 151         dst_release(&rt->u.dst);
 152         call_rcu_bh(&rt->u.dst.rcu_head, dst_rcu_free);
 153 }
 154
 155 static void dn_dst_check_expire(unsigned long dummy)
 156 {
 157         int i;
 158         struct dn_route *rt, **rtp;
 159         unsigned long now = jiffies;
 160         unsigned long expire = 120 * HZ;
 161
 162         for(i = 0; i <= dn_rt_hash_mask; i++) {
 163                 rtp = &dn_rt_hash_table[i].chain;
 164
 165                 spin_lock(&dn_rt_hash_table[i].lock);
 166                 while((rt=*rtp) != NULL) {
 167                         if (atomic_read(&rt->u.dst.__refcnt) ||
 168                                         (now - rt->u.dst.lastuse) < expire) {
 169                                 rtp = &rt->u.rt_next;
 170                                 continue;
 171                         }
 172                         *rtp = rt->u.rt_next;
 173                         rt->u.rt_next = NULL;
 174                         dnrt_free(rt);
 175                 }
 176                 spin_unlock(&dn_rt_hash_table[i].lock);
 177
 178                 if ((jiffies - now) > 0)
 179                         break;
 180         }
 181
 182         mod_timer(&dn_route_timer, now + decnet_dst_gc_interval * HZ);
 183 }
 184
 185 static int dn_dst_gc(void)
 186 {
 187         struct dn_route *rt, **rtp;
 188         int i;
 189         unsigned long now = jiffies;
 190         unsigned long expire = 10 * HZ;
 191
 192         for(i = 0; i <= dn_rt_hash_mask; i++) {
 193
 194                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 195                 rtp = &dn_rt_hash_table[i].chain;
 196
 197                 while((rt=*rtp) != NULL) {
 198                         if (atomic_read(&rt->u.dst.__refcnt) ||
 199                                         (now - rt->u.dst.lastuse) < expire) {
 200                                 rtp = &rt->u.rt_next;
 201                                 continue;
 202                         }
 203                         *rtp = rt->u.rt_next;
 204                         rt->u.rt_next = NULL;
 205                         dnrt_drop(rt);
 206                         break;
 207                 }
 208                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 209         }
 210
 211         return 0;
 212 }
 213
 214 /*
 215  * The decnet standards don't impose a particular minimum mtu, what they
 216  * do insist on is that the routing layer accepts a datagram of at least
 217  * 230 bytes long. Here we have to subtract the routing header length from
 218  * 230 to get the minimum acceptable mtu. If there is no neighbour, then we
 219  * assume the worst and use a long header size.
 220  *
 221  * We update both the mtu and the advertised mss (i.e. the segment size we
 222  * advertise to the other end).
 223  */
 224 static void dn_dst_update_pmtu(struct dst_entry *dst, u32 mtu)
 225 {
 226         u32 min_mtu = 230;
 227         struct dn_dev *dn = dst->neighbour ?
 228                             (struct dn_dev *)dst->neighbour->dev->dn_ptr : NULL;
 229
 230         if (dn && dn->use_long == 0)
 231                 min_mtu -= 6;
 232         else
 233                 min_mtu -= 21;
 234
 235         if (dst->metrics[RTAX_MTU-1] > mtu && mtu >= min_mtu) {
 236                 if (!(dst_metric_locked(dst, RTAX_MTU))) {
 237                         dst->metrics[RTAX_MTU-1] = mtu;
 238                         dst_set_expires(dst, dn_rt_mtu_expires);
 239                 }
 240                 if (!(dst_metric_locked(dst, RTAX_ADVMSS))) {
 241                         u32 mss = mtu - DN_MAX_NSP_DATA_HEADER;
 242                         if (dst->metrics[RTAX_ADVMSS-1] > mss)
 243                                 dst->metrics[RTAX_ADVMSS-1] = mss;
 244                 }
 245         }
 246 }
 247
 248 /*
 249  * When a route has been marked obsolete. (e.g. routing cache flush)
 250  */
 251 static struct dst_entry *dn_dst_check(struct dst_entry *dst, __u32 cookie)
 252 {
 253         return NULL;
 254 }
 255
 256 static struct dst_entry *dn_dst_negative_advice(struct dst_entry *dst)
 257 {
 258         dst_release(dst);
 259         return NULL;
 260 }
 261
 262 static void dn_dst_link_failure(struct sk_buff *skb)
 263 {
 264         return;
 265 }
 266
 267 static inline int compare_keys(struct flowi *fl1, struct flowi *fl2)
 268 {
 269         return memcmp(&fl1->nl_u.dn_u, &fl2->nl_u.dn_u, sizeof(fl1->nl_u.dn_u)) == 0 &&
 270                 fl1->oif == fl2->oif &&
 271                 fl1->iif == fl2->iif;
 272 }
 273
 274 static int dn_insert_route(struct dn_route *rt, unsigned hash, struct dn_route **rp)
 275 {
 276         struct dn_route *rth, **rthp;
 277         unsigned long now = jiffies;
 278
 279         rthp = &dn_rt_hash_table[hash].chain;
 280
 281         spin_lock_bh(&dn_rt_hash_table[hash].lock);
 282         while((rth = *rthp) != NULL) {
 283                 if (compare_keys(&rth->fl, &rt->fl)) {
 284                         /* Put it first */
 285                         *rthp = rth->u.rt_next;
 286                         rcu_assign_pointer(rth->u.rt_next,
 287                                            dn_rt_hash_table[hash].chain);
 288                         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rth);
 289
 290                         rth->u.dst.__use++;
 291                         dst_hold(&rth->u.dst);
 292                         rth->u.dst.lastuse = now;
 293                         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 294
 295                         dnrt_drop(rt);
 296                         *rp = rth;
 297                         return 0;
 298                 }
 299                 rthp = &rth->u.rt_next;
 300         }
 301
 302         rcu_assign_pointer(rt->u.rt_next, dn_rt_hash_table[hash].chain);
 303         rcu_assign_pointer(dn_rt_hash_table[hash].chain, rt);
 304
 305         dst_hold(&rt->u.dst);
 306         rt->u.dst.__use++;
 307         rt->u.dst.lastuse = now;
 308         spin_unlock_bh(&dn_rt_hash_table[hash].lock);
 309         *rp = rt;
 310         return 0;
 311 }
 312
 313 void dn_run_flush(unsigned long dummy)
 314 {
 315         int i;
 316         struct dn_route *rt, *next;
 317
 318         for(i = 0; i < dn_rt_hash_mask; i++) {
 319                 spin_lock_bh(&dn_rt_hash_table[i].lock);
 320
 321                 if ((rt = xchg(&dn_rt_hash_table[i].chain, NULL)) == NULL)
 322                         goto nothing_to_declare;
 323
 324                 for(; rt; rt=next) {
 325                         next = rt->u.rt_next;
 326                         rt->u.rt_next = NULL;
 327                         dst_free((struct dst_entry *)rt);
 328                 }
 329
 330 nothing_to_declare:
 331                 spin_unlock_bh(&dn_rt_hash_table[i].lock);
 332         }
 333 }
 334
 335 static DEFINE_SPINLOCK(dn_rt_flush_lock);
 336
 337 void dn_rt_cache_flush(int delay)
 338 {
 339         unsigned long now = jiffies;
 340         int user_mode = !in_interrupt();
 341
 342         if (delay < 0)
 343                 delay = dn_rt_min_delay;
 344
 345         spin_lock_bh(&dn_rt_flush_lock);
 346
 347         if (del_timer(&dn_rt_flush_timer) && delay > 0 && dn_rt_deadline) {
 348                 long tmo = (long)(dn_rt_deadline - now);
 349
 350                 if (user_mode && tmo < dn_rt_max_delay - dn_rt_min_delay)
 351                         tmo = 0;
 352
 353                 if (delay > tmo)
 354                         delay = tmo;
 355         }
 356
 357         if (delay <= 0) {
 358                 spin_unlock_bh(&dn_rt_flush_lock);
 359                 dn_run_flush(0);
 360                 return;
 361         }
 362
 363         if (dn_rt_deadline == 0)
 364                 dn_rt_deadline = now + dn_rt_max_delay;
 365
 366         dn_rt_flush_timer.expires = now + delay;
 367         add_timer(&dn_rt_flush_timer);
 368         spin_unlock_bh(&dn_rt_flush_lock);
 369 }
 370
 371 /**
 372  * dn_return_short - Return a short packet to its sender
 373  * @skb: The packet to return
 374  *
 375  */
 376 static int dn_return_short(struct sk_buff *skb)
 377 {
 378         struct dn_skb_cb *cb;
 379         unsigned char *ptr;
 380         __le16 *src;
 381         __le16 *dst;
 382         __le16 tmp;
 383
 384         /* Add back headers */
 385         skb_push(skb, skb->data - skb->nh.raw);
 386
 387         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 388                 return NET_RX_DROP;
 389
 390         cb = DN_SKB_CB(skb);
 391         /* Skip packet length and point to flags */
 392         ptr = skb->data + 2;
 393         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 394
 395         dst = (__le16 *)ptr;
 396         ptr += 2;
 397         src = (__le16 *)ptr;
 398         ptr += 2;
 399         *ptr = 0; /* Zero hop count */
 400
 401         /* Swap source and destination */
 402         tmp  = *src;
 403         *src = *dst;
 404         *dst = tmp;
 405
 406         skb->pkt_type = PACKET_OUTGOING;
 407         dn_rt_finish_output(skb, NULL, NULL);
 408         return NET_RX_SUCCESS;
 409 }
 410
 411 /**
 412  * dn_return_long - Return a long packet to its sender
 413  * @skb: The long format packet to return
 414  *
 415  */
 416 static int dn_return_long(struct sk_buff *skb)
 417 {
 418         struct dn_skb_cb *cb;
 419         unsigned char *ptr;
 420         unsigned char *src_addr, *dst_addr;
 421         unsigned char tmp[ETH_ALEN];
 422
 423         /* Add back all headers */
 424         skb_push(skb, skb->data - skb->nh.raw);
 425
 426         if ((skb = skb_unshare(skb, GFP_ATOMIC)) == NULL)
 427                 return NET_RX_DROP;
 428
 429         cb = DN_SKB_CB(skb);
 430         /* Ignore packet length and point to flags */
 431         ptr = skb->data + 2;
 432
 433         /* Skip padding */
 434         if (*ptr & DN_RT_F_PF) {
 435                 char padlen = (*ptr & ~DN_RT_F_PF);
 436                 ptr += padlen;
 437         }
 438
 439         *ptr++ = (cb->rt_flags & ~DN_RT_F_RQR) | DN_RT_F_RTS;
 440         ptr += 2;
 441         dst_addr = ptr;
 442         ptr += 8;
 443         src_addr = ptr;
 444         ptr += 6;
 445         *ptr = 0; /* Zero hop count */
 446
 447         /* Swap source and destination */
 448         memcpy(tmp, src_addr, ETH_ALEN);
 449         memcpy(src_addr, dst_addr, ETH_ALEN);
 450         memcpy(dst_addr, tmp, ETH_ALEN);
 451
 452         skb->pkt_type = PACKET_OUTGOING;
 453         dn_rt_finish_output(skb, dst_addr, src_addr);
 454         return NET_RX_SUCCESS;
 455 }
 456
 457 /**
 458  * dn_route_rx_packet - Try and find a route for an incoming packet
 459  * @skb: The packet to find a route for
 460  *
 461  * Returns: result of input function if route is found, error code otherwise
 462  */
 463 static int dn_route_rx_packet(struct sk_buff *skb)
 464 {
 465         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 466         int err;
 467
 468         if ((err = dn_route_input(skb)) == 0)
 469                 return dst_input(skb);
 470
 471         if (decnet_debug_level & 4) {
 472                 char *devname = skb->dev ? skb->dev->name : "???";
 473                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
 474                 printk(KERN_DEBUG
 475                         "DECnet: dn_route_rx_packet: rt_flags=0x%02x dev=%s len=%d src=0x%04hx dst=0x%04hx err=%d type=%d\n",
 476                         (int)cb->rt_flags, devname, skb->len,
 477                         dn_ntohs(cb->src), dn_ntohs(cb->dst),
 478                         err, skb->pkt_type);
 479         }
 480
 481         if ((skb->pkt_type == PACKET_HOST) && (cb->rt_flags & DN_RT_F_RQR)) {
 482                 switch(cb->rt_flags & DN_RT_PKT_MSK) {
 483                         case DN_RT_PKT_SHORT:
 484                                 return dn_return_short(skb);
 485                         case DN_RT_PKT_LONG:
 486                                 return dn_return_long(skb);
 487                 }
 488         }
 489
 490         kfree_skb(skb);
 491         return NET_RX_DROP;
 492 }
 493
 494 static int dn_route_rx_long(struct sk_buff *skb)
 495 {
 496         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 497         unsigned char *ptr = skb->data;
 498
 499         if (!pskb_may_pull(skb, 21)) /* 20 for long header, 1 for shortest nsp */
 500                 goto drop_it;
 501
 502         skb_pull(skb, 20);
 503         skb->h.raw = skb->data;
 504
 505         /* Destination info */
 506         ptr += 2;
 507         cb->dst = dn_eth2dn(ptr);
 508         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 509                 goto drop_it;
 510         ptr += 6;
 511
 512
 513         /* Source info */
 514         ptr += 2;
 515         cb->src = dn_eth2dn(ptr);
 516         if (memcmp(ptr, dn_hiord_addr, 4) != 0)
 517                 goto drop_it;
 518         ptr += 6;
 519         /* Other junk */
 520         ptr++;
 521         cb->hops = *ptr++; /* Visit Count */
 522
 523         return NF_HOOK(PF_DECnet, NF_DN_PRE_ROUTING, skb, skb->dev, NULL, dn_route_rx_packet);
 524
 525 drop_it:
 526         kfree_skb(skb);
 527         return NET_RX_DROP;
 528 }
 529
 530
 531
 532 static int dn_route_rx_short(struct sk_buff *skb)
 533 {
 534         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 535         unsigned char *ptr = skb->data;
 536
 537         if (!pskb_may_pull(skb, 6)) /* 5 for short header + 1 for shortest nsp */
 538                 goto drop_it;
 539
 540         skb_pull(skb, 5);
 541         skb->h.raw = skb->data;
 542
 543         cb->dst = *(__le16 *)ptr;
 544         ptr += 2;
 545         cb->src = *(__le16 *)ptr;
 546         ptr += 2;
 547         cb->hops = *ptr & 0x3f;
 548
 549         return NF_HOOK(PF_DECnet, NF_DN_PRE_ROUTING, skb, skb->dev, NULL, dn_route_rx_packet);
 550
 551 drop_it:
 552         kfree_skb(skb);
 553         return NET_RX_DROP;
 554 }
 555
 556 static int dn_route_discard(struct sk_buff *skb)
 557 {
 558         /*
 559          * I know we drop the packet here, but thats considered success in
 560          * this case
 561          */
 562         kfree_skb(skb);
 563         return NET_RX_SUCCESS;
 564 }
 565
 566 static int dn_route_ptp_hello(struct sk_buff *skb)
 567 {
 568         dn_dev_hello(skb);
 569         dn_neigh_pointopoint_hello(skb);
 570         return NET_RX_SUCCESS;
 571 }
 572
 573 int dn_route_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt, struct net_device *orig_dev)
 574 {
 575         struct dn_skb_cb *cb;
 576         unsigned char flags = 0;
 577         __u16 len = dn_ntohs(*(__le16 *)skb->data);
 578         struct dn_dev *dn = (struct dn_dev *)dev->dn_ptr;
 579         unsigned char padlen = 0;
 580
 581         if (dn == NULL)
 582                 goto dump_it;
 583
 584         if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
 585                 goto out;
 586
 587         if (!pskb_may_pull(skb, 3))
 588                 goto dump_it;
 589
 590         skb_pull(skb, 2);
 591
 592         if (len > skb->len)
 593                 goto dump_it;
 594
 595         skb_trim(skb, len);
 596
 597         flags = *skb->data;
 598
 599         cb = DN_SKB_CB(skb);
 600         cb->stamp = jiffies;
 601         cb->iif = dev->ifindex;
 602
 603         /*
 604          * If we have padding, remove it.
 605          */
 606         if (flags & DN_RT_F_PF) {
 607                 padlen = flags & ~DN_RT_F_PF;
 608                 if (!pskb_may_pull(skb, padlen + 1))
 609                         goto dump_it;
 610                 skb_pull(skb, padlen);
 611                 flags = *skb->data;
 612         }
 613
 614         skb->nh.raw = skb->data;
 615
 616         /*
 617          * Weed out future version DECnet
 618          */
 619         if (flags & DN_RT_F_VER)
 620                 goto dump_it;
 621
 622         cb->rt_flags = flags;
 623
 624         if (decnet_debug_level & 1)
 625                 printk(KERN_DEBUG
 626                         "dn_route_rcv: got 0x%02x from %s [%d %d %d]\n",
 627                         (int)flags, (dev) ? dev->name : "???", len, skb->len,
 628                         padlen);
 629
 630         if (flags & DN_RT_PKT_CNTL) {
 631                 if (unlikely(skb_linearize(skb)))
 632                         goto dump_it;
 633
 634                 switch(flags & DN_RT_CNTL_MSK) {
 635                         case DN_RT_PKT_INIT:
 636                                 dn_dev_init_pkt(skb);
 637                                 break;
 638                         case DN_RT_PKT_VERI:
 639                                 dn_dev_veri_pkt(skb);
 640                                 break;
 641                 }
 642
 643                 if (dn->parms.state != DN_DEV_S_RU)
 644                         goto dump_it;
 645
 646                 switch(flags & DN_RT_CNTL_MSK) {
 647                         case DN_RT_PKT_HELO:
 648                                 return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_route_ptp_hello);
 649
 650                         case DN_RT_PKT_L1RT:
 651                         case DN_RT_PKT_L2RT:
 652                                 return NF_HOOK(PF_DECnet, NF_DN_ROUTE, skb, skb->dev, NULL, dn_route_discard);
 653                         case DN_RT_PKT_ERTH:
 654                                 return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_router_hello);
 655
 656                         case DN_RT_PKT_EEDH:
 657                                 return NF_HOOK(PF_DECnet, NF_DN_HELLO, skb, skb->dev, NULL, dn_neigh_endnode_hello);
 658                 }
 659         } else {
 660                 if (dn->parms.state != DN_DEV_S_RU)
 661                         goto dump_it;
 662
 663                 skb_pull(skb, 1); /* Pull flags */
 664
 665                 switch(flags & DN_RT_PKT_MSK) {
 666                         case DN_RT_PKT_LONG:
 667                                 return dn_route_rx_long(skb);
 668                         case DN_RT_PKT_SHORT:
 669                                 return dn_route_rx_short(skb);
 670                 }
 671         }
 672
 673 dump_it:
 674         kfree_skb(skb);
 675 out:
 676         return NET_RX_DROP;
 677 }
 678
 679 static int dn_output(struct sk_buff *skb)
 680 {
 681         struct dst_entry *dst = skb->dst;
 682         struct dn_route *rt = (struct dn_route *)dst;
 683         struct net_device *dev = dst->dev;
 684         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 685         struct neighbour *neigh;
 686
 687         int err = -EINVAL;
 688
 689         if ((neigh = dst->neighbour) == NULL)
 690                 goto error;
 691
 692         skb->dev = dev;
 693
 694         cb->src = rt->rt_saddr;
 695         cb->dst = rt->rt_daddr;
 696
 697         /*
 698          * Always set the Intra-Ethernet bit on all outgoing packets
 699          * originated on this node. Only valid flag from upper layers
 700          * is return-to-sender-requested. Set hop count to 0 too.
 701          */
 702         cb->rt_flags &= ~DN_RT_F_RQR;
 703         cb->rt_flags |= DN_RT_F_IE;
 704         cb->hops = 0;
 705
 706         return NF_HOOK(PF_DECnet, NF_DN_LOCAL_OUT, skb, NULL, dev, neigh->output);
 707
 708 error:
 709         if (net_ratelimit())
 710                 printk(KERN_DEBUG "dn_output: This should not happen\n");
 711
 712         kfree_skb(skb);
 713
 714         return err;
 715 }
 716
 717 static int dn_forward(struct sk_buff *skb)
 718 {
 719         struct dn_skb_cb *cb = DN_SKB_CB(skb);
 720         struct dst_entry *dst = skb->dst;
 721         struct dn_dev *dn_db = dst->dev->dn_ptr;
 722         struct dn_route *rt;
 723         struct neighbour *neigh = dst->neighbour;
 724         int header_len;
 725 #ifdef CONFIG_NETFILTER
 726         struct net_device *dev = skb->dev;
 727 #endif
 728
 729         if (skb->pkt_type != PACKET_HOST)
 730                 goto drop;
 731
 732         /* Ensure that we have enough space for headers */
 733         rt = (struct dn_route *)skb->dst;
 734         header_len = dn_db->use_long ? 21 : 6;
 735         if (skb_cow(skb, LL_RESERVED_SPACE(rt->u.dst.dev)+header_len))
 736                 goto drop;
 737
 738         /*
 739          * Hop count exceeded.
 740          */
 741         if (++cb->hops > 30)
 742                 goto drop;
 743
 744         skb->dev = rt->u.dst.dev;
 745
 746         /*
 747          * If packet goes out same interface it came in on, then set
 748          * the Intra-Ethernet bit. This has no effect for short
 749          * packets, so we don't need to test for them here.
 750          */
 751         cb->rt_flags &= ~DN_RT_F_IE;
 752         if (rt->rt_flags & RTCF_DOREDIRECT)
 753                 cb->rt_flags |= DN_RT_F_IE;
 754
 755         return NF_HOOK(PF_DECnet, NF_DN_FORWARD, skb, dev, skb->dev, neigh->output);
 756
 757 drop:
 758         kfree_skb(skb);
 759         return NET_RX_DROP;
 760 }
 761
 762 /*
 763  * Drop packet. This is used for endnodes and for
 764  * when we should not be forwarding packets from
 765  * this dest.
 766  */
 767 static int dn_blackhole(struct sk_buff *skb)
 768 {
 769         kfree_skb(skb);
 770         return NET_RX_DROP;
 771 }
 772
 773 /*
 774  * Used to catch bugs. This should never normally get
 775  * called.
 776  */
 777 static int dn_rt_bug(struct sk_buff *skb)
 778 {
 779         if (net_ratelimit()) {
 780                 struct dn_skb_cb *cb = DN_SKB_CB(skb);
 781
 782                 printk(KERN_DEBUG "dn_rt_bug: skb from:%04x to:%04x\n",
 783                                 dn_ntohs(cb->src), dn_ntohs(cb->dst));
 784         }
 785
 786         kfree_skb(skb);
 787
 788         return NET_RX_BAD;
 789 }
 790
 791 static int dn_rt_set_next_hop(struct dn_route *rt, struct dn_fib_res *res)
 792 {
 793         struct dn_fib_info *fi = res->fi;
 794         struct net_device *dev = rt->u.dst.dev;
 795         struct neighbour *n;
 796         unsigned mss;
 797
 798         if (fi) {
 799                 if (DN_FIB_RES_GW(*res) &&
 800                     DN_FIB_RES_NH(*res).nh_scope == RT_SCOPE_LINK)
 801                         rt->rt_gateway = DN_FIB_RES_GW(*res);
 802                 memcpy(rt->u.dst.metrics, fi->fib_metrics,
 803                        sizeof(rt->u.dst.metrics));
 804         }
 805         rt->rt_type = res->type;
 806
 807         if (dev != NULL && rt->u.dst.neighbour == NULL) {
 808                 n = __neigh_lookup_errno(&dn_neigh_table, &rt->rt_gateway, dev);
 809                 if (IS_ERR(n))
 810                         return PTR_ERR(n);
 811                 rt->u.dst.neighbour = n;
 812         }
 813
 814         if (rt->u.dst.metrics[RTAX_MTU-1] == 0 ||
 815             rt->u.dst.metrics[RTAX_MTU-1] > rt->u.dst.dev->mtu)
 816                 rt->u.dst.metrics[RTAX_MTU-1] = rt->u.dst.dev->mtu;
 817         mss = dn_mss_from_pmtu(dev, dst_mtu(&rt->u.dst));
 818         if (rt->u.dst.metrics[RTAX_ADVMSS-1] == 0 ||
 819             rt->u.dst.metrics[RTAX_ADVMSS-1] > mss)
 820                 rt->u.dst.metrics[RTAX_ADVMSS-1] = mss;
 821         return 0;
 822 }
 823
 824 static inline int dn_match_addr(__le16 addr1, __le16 addr2)
 825 {
 826         __u16 tmp = dn_ntohs(addr1) ^ dn_ntohs(addr2);
 827         int match = 16;
 828         while(tmp) {
 829                 tmp >>= 1;
 830                 match--;
 831         }
 832         return match;
 833 }
 834
 835 static __le16 dnet_select_source(const struct net_device *dev, __le16 daddr, int scope)
 836 {
 837         __le16 saddr = 0;
 838         struct dn_dev *dn_db = dev->dn_ptr;
 839         struct dn_ifaddr *ifa;
 840         int best_match = 0;
 841         int ret;
 842
 843         read_lock(&dev_base_lock);
 844         for(ifa = dn_db->ifa_list; ifa; ifa = ifa->ifa_next) {
 845                 if (ifa->ifa_scope > scope)
 846                         continue;
 847                 if (!daddr) {
 848                         saddr = ifa->ifa_local;
 849                         break;
 850                 }
 851                 ret = dn_match_addr(daddr, ifa->ifa_local);
 852                 if (ret > best_match)
 853                         saddr = ifa->ifa_local;
 854                 if (best_match == 0)
 855                         saddr = ifa->ifa_local;
 856         }
 857         read_unlock(&dev_base_lock);
 858
 859         return saddr;
 860 }
 861
 862 static inline __le16 __dn_fib_res_prefsrc(struct dn_fib_res *res)
 863 {
 864         return dnet_select_source(DN_FIB_RES_DEV(*res), DN_FIB_RES_GW(*res), res->scope);
 865 }
 866
 867 static inline __le16 dn_fib_rules_map_destination(__le16 daddr, struct dn_fib_res *res)
 868 {
 869         __le16 mask = dnet_make_mask(res->prefixlen);
 870         return (daddr&~mask)|res->fi->fib_nh->nh_gw;
 871 }
 872
 873 static int dn_route_output_slow(struct dst_entry **pprt, const struct flowi *oldflp, int try_hard)
 874 {
 875         struct flowi fl = { .nl_u = { .dn_u =
 876                                       { .daddr = oldflp->fld_dst,
 877                                         .saddr = oldflp->fld_src,
 878                                         .scope = RT_SCOPE_UNIVERSE,
 879 #ifdef CONFIG_DECNET_ROUTE_FWMARK
 880                                         .fwmark = oldflp->fld_fwmark
 881 #endif
 882                                      } },
 883                             .iif = loopback_dev.ifindex,
 884                             .oif = oldflp->oif };
 885         struct dn_route *rt = NULL;
 886         struct net_device *dev_out = NULL;
 887         struct neighbour *neigh = NULL;
 888         unsigned hash;
 889         unsigned flags = 0;
 890         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNICAST };
 891         int err;
 892         int free_res = 0;
 893         __le16 gateway = 0;
 894
 895         if (decnet_debug_level & 16)
 896                 printk(KERN_DEBUG
 897                        "dn_route_output_slow: dst=%04x src=%04x mark=%d"
 898                        " iif=%d oif=%d\n", dn_ntohs(oldflp->fld_dst),
 899                        dn_ntohs(oldflp->fld_src),
 900                        oldflp->fld_fwmark, loopback_dev.ifindex, oldflp->oif);
 901
 902         /* If we have an output interface, verify its a DECnet device */
 903         if (oldflp->oif) {
 904                 dev_out = dev_get_by_index(oldflp->oif);
 905                 err = -ENODEV;
 906                 if (dev_out && dev_out->dn_ptr == NULL) {
 907                         dev_put(dev_out);
 908                         dev_out = NULL;
 909                 }
 910                 if (dev_out == NULL)
 911                         goto out;
 912         }
 913
 914         /* If we have a source address, verify that its a local address */
 915         if (oldflp->fld_src) {
 916                 err = -EADDRNOTAVAIL;
 917
 918                 if (dev_out) {
 919                         if (dn_dev_islocal(dev_out, oldflp->fld_src))
 920                                 goto source_ok;
 921                         dev_put(dev_out);
 922                         goto out;
 923                 }
 924                 read_lock(&dev_base_lock);
 925                 for(dev_out = dev_base; dev_out; dev_out = dev_out->next) {
 926                         if (!dev_out->dn_ptr)
 927                                 continue;
 928                         if (!dn_dev_islocal(dev_out, oldflp->fld_src))
 929                                 continue;
 930                         if ((dev_out->flags & IFF_LOOPBACK) &&
 931                             oldflp->fld_dst &&
 932                             !dn_dev_islocal(dev_out, oldflp->fld_dst))
 933                                 continue;
 934                         break;
 935                 }
 936                 read_unlock(&dev_base_lock);
 937                 if (dev_out == NULL)
 938                         goto out;
 939                 dev_hold(dev_out);
 940 source_ok:
 941                 ;
 942         }
 943
 944         /* No destination? Assume its local */
 945         if (!fl.fld_dst) {
 946                 fl.fld_dst = fl.fld_src;
 947
 948                 err = -EADDRNOTAVAIL;
 949                 if (dev_out)
 950                         dev_put(dev_out);
 951                 dev_out = &loopback_dev;
 952                 dev_hold(dev_out);
 953                 if (!fl.fld_dst) {
 954                         fl.fld_dst =
 955                         fl.fld_src = dnet_select_source(dev_out, 0,
 956                                                        RT_SCOPE_HOST);
 957                         if (!fl.fld_dst)
 958                                 goto out;
 959                 }
 960                 fl.oif = loopback_dev.ifindex;
 961                 res.type = RTN_LOCAL;
 962                 goto make_route;
 963         }
 964
 965         if (decnet_debug_level & 16)
 966                 printk(KERN_DEBUG
 967                        "dn_route_output_slow: initial checks complete."
 968                        " dst=%o4x src=%04x oif=%d try_hard=%d\n",
 969                        dn_ntohs(fl.fld_dst), dn_ntohs(fl.fld_src),
 970                        fl.oif, try_hard);
 971
 972         /*
 973          * N.B. If the kernel is compiled without router support then
 974          * dn_fib_lookup() will evaluate to non-zero so this if () block
 975          * will always be executed.
 976          */
 977         err = -ESRCH;
 978         if (try_hard || (err = dn_fib_lookup(&fl, &res)) != 0) {
 979                 struct dn_dev *dn_db;
 980                 if (err != -ESRCH)
 981                         goto out;
 982                 /*
 983                  * Here the fallback is basically the standard algorithm for
 984                  * routing in endnodes which is described in the DECnet routing
 985                  * docs
 986                  *
 987                  * If we are not trying hard, look in neighbour cache.
 988                  * The result is tested to ensure that if a specific output
 989                  * device/source address was requested, then we honour that
 990                  * here
 991                  */
 992                 if (!try_hard) {
 993                         neigh = neigh_lookup_nodev(&dn_neigh_table, &fl.fld_dst);
 994                         if (neigh) {
 995                                 if ((oldflp->oif &&
 996                                     (neigh->dev->ifindex != oldflp->oif)) ||
 997                                     (oldflp->fld_src &&
 998                                     (!dn_dev_islocal(neigh->dev,
 999                                                       oldflp->fld_src)))) {
1000                                         neigh_release(neigh);
1001                                         neigh = NULL;
1002                                 } else {
1003                                         if (dev_out)
1004                                                 dev_put(dev_out);
1005                                         if (dn_dev_islocal(neigh->dev, fl.fld_dst)) {
1006                                                 dev_out = &loopback_dev;
1007                                                 res.type = RTN_LOCAL;
1008                                         } else {
1009                                                 dev_out = neigh->dev;
1010                                         }
1011                                         dev_hold(dev_out);
1012                                         goto select_source;
1013                                 }
1014                         }
1015                 }
1016
1017                 /* Not there? Perhaps its a local address */
1018                 if (dev_out == NULL)
1019                         dev_out = dn_dev_get_default();
1020                 err = -ENODEV;
1021                 if (dev_out == NULL)
1022                         goto out;
1023                 dn_db = dev_out->dn_ptr;
1024                 /* Possible improvement - check all devices for local addr */
1025                 if (dn_dev_islocal(dev_out, fl.fld_dst)) {
1026                         dev_put(dev_out);
1027                         dev_out = &loopback_dev;
1028                         dev_hold(dev_out);
1029                         res.type = RTN_LOCAL;
1030                         goto select_source;
1031                 }
1032                 /* Not local either.... try sending it to the default router */
1033                 neigh = neigh_clone(dn_db->router);
1034                 BUG_ON(neigh && neigh->dev != dev_out);
1035
1036                 /* Ok then, we assume its directly connected and move on */
1037 select_source:
1038                 if (neigh)
1039                         gateway = ((struct dn_neigh *)neigh)->addr;
1040                 if (gateway == 0)
1041                         gateway = fl.fld_dst;
1042                 if (fl.fld_src == 0) {
1043                         fl.fld_src = dnet_select_source(dev_out, gateway,
1044                                                          res.type == RTN_LOCAL ?
1045                                                          RT_SCOPE_HOST :
1046                                                          RT_SCOPE_LINK);
1047                         if (fl.fld_src == 0 && res.type != RTN_LOCAL)
1048                                 goto e_addr;
1049                 }
1050                 fl.oif = dev_out->ifindex;
1051                 goto make_route;
1052         }
1053         free_res = 1;
1054
1055         if (res.type == RTN_NAT)
1056                 goto e_inval;
1057
1058         if (res.type == RTN_LOCAL) {
1059                 if (!fl.fld_src)
1060                         fl.fld_src = fl.fld_dst;
1061                 if (dev_out)
1062                         dev_put(dev_out);
1063                 dev_out = &loopback_dev;
1064                 dev_hold(dev_out);
1065                 fl.oif = dev_out->ifindex;
1066                 if (res.fi)
1067                         dn_fib_info_put(res.fi);
1068                 res.fi = NULL;
1069                 goto make_route;
1070         }
1071
1072         if (res.fi->fib_nhs > 1 && fl.oif == 0)
1073                 dn_fib_select_multipath(&fl, &res);
1074
1075         /*
1076          * We could add some logic to deal with default routes here and
1077          * get rid of some of the special casing above.
1078          */
1079
1080         if (!fl.fld_src)
1081                 fl.fld_src = DN_FIB_RES_PREFSRC(res);
1082
1083         if (dev_out)
1084                 dev_put(dev_out);
1085         dev_out = DN_FIB_RES_DEV(res);
1086         dev_hold(dev_out);
1087         fl.oif = dev_out->ifindex;
1088         gateway = DN_FIB_RES_GW(res);
1089
1090 make_route:
1091         if (dev_out->flags & IFF_LOOPBACK)
1092                 flags |= RTCF_LOCAL;
1093
1094         rt = dst_alloc(&dn_dst_ops);
1095         if (rt == NULL)
1096                 goto e_nobufs;
1097
1098         atomic_set(&rt->u.dst.__refcnt, 1);
1099         rt->u.dst.flags   = DST_HOST;
1100
1101         rt->fl.fld_src    = oldflp->fld_src;
1102         rt->fl.fld_dst    = oldflp->fld_dst;
1103         rt->fl.oif        = oldflp->oif;
1104         rt->fl.iif        = 0;
1105 #ifdef CONFIG_DECNET_ROUTE_FWMARK
1106         rt->fl.fld_fwmark = oldflp->fld_fwmark;
1107 #endif
1108
1109         rt->rt_saddr      = fl.fld_src;
1110         rt->rt_daddr      = fl.fld_dst;
1111         rt->rt_gateway    = gateway ? gateway : fl.fld_dst;
1112         rt->rt_local_src  = fl.fld_src;
1113
1114         rt->rt_dst_map    = fl.fld_dst;
1115         rt->rt_src_map    = fl.fld_src;
1116
1117         rt->u.dst.dev = dev_out;
1118         dev_hold(dev_out);
1119         rt->u.dst.neighbour = neigh;
1120         neigh = NULL;
1121
1122         rt->u.dst.lastuse = jiffies;
1123         rt->u.dst.output  = dn_output;
1124         rt->u.dst.input   = dn_rt_bug;
1125         rt->rt_flags      = flags;
1126         if (flags & RTCF_LOCAL)
1127                 rt->u.dst.input = dn_nsp_rx;
1128
1129         err = dn_rt_set_next_hop(rt, &res);
1130         if (err)
1131                 goto e_neighbour;
1132
1133         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1134         dn_insert_route(rt, hash, (struct dn_route **)pprt);
1135
1136 done:
1137         if (neigh)
1138                 neigh_release(neigh);
1139         if (free_res)
1140                 dn_fib_res_put(&res);
1141         if (dev_out)
1142                 dev_put(dev_out);
1143 out:
1144         return err;
1145
1146 e_addr:
1147         err = -EADDRNOTAVAIL;
1148         goto done;
1149 e_inval:
1150         err = -EINVAL;
1151         goto done;
1152 e_nobufs:
1153         err = -ENOBUFS;
1154         goto done;
1155 e_neighbour:
1156         dst_free(&rt->u.dst);
1157         goto e_nobufs;
1158 }
1159
1160
1161 /*
1162  * N.B. The flags may be moved into the flowi at some future stage.
1163  */
1164 static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *flp, int flags)
1165 {
1166         unsigned hash = dn_hash(flp->fld_src, flp->fld_dst);
1167         struct dn_route *rt = NULL;
1168
1169         if (!(flags & MSG_TRYHARD)) {
1170                 rcu_read_lock_bh();
1171                 for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt;
1172                         rt = rcu_dereference(rt->u.rt_next)) {
1173                         if ((flp->fld_dst == rt->fl.fld_dst) &&
1174                             (flp->fld_src == rt->fl.fld_src) &&
1175 #ifdef CONFIG_DECNET_ROUTE_FWMARK
1176                             (flp->fld_fwmark == rt->fl.fld_fwmark) &&
1177 #endif
1178                             (rt->fl.iif == 0) &&
1179                             (rt->fl.oif == flp->oif)) {
1180                                 rt->u.dst.lastuse = jiffies;
1181                                 dst_hold(&rt->u.dst);
1182                                 rt->u.dst.__use++;
1183                                 rcu_read_unlock_bh();
1184                                 *pprt = &rt->u.dst;
1185                                 return 0;
1186                         }
1187                 }
1188                 rcu_read_unlock_bh();
1189         }
1190
1191         return dn_route_output_slow(pprt, flp, flags);
1192 }
1193
1194 static int dn_route_output_key(struct dst_entry **pprt, struct flowi *flp, int flags)
1195 {
1196         int err;
1197
1198         err = __dn_route_output_key(pprt, flp, flags);
1199         if (err == 0 && flp->proto) {
1200                 err = xfrm_lookup(pprt, flp, NULL, 0);
1201         }
1202         return err;
1203 }
1204
1205 int dn_route_output_sock(struct dst_entry **pprt, struct flowi *fl, struct sock *sk, int flags)
1206 {
1207         int err;
1208
1209         err = __dn_route_output_key(pprt, fl, flags & MSG_TRYHARD);
1210         if (err == 0 && fl->proto) {
1211                 err = xfrm_lookup(pprt, fl, sk, !(flags & MSG_DONTWAIT));
1212         }
1213         return err;
1214 }
1215
1216 static int dn_route_input_slow(struct sk_buff *skb)
1217 {
1218         struct dn_route *rt = NULL;
1219         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1220         struct net_device *in_dev = skb->dev;
1221         struct net_device *out_dev = NULL;
1222         struct dn_dev *dn_db;
1223         struct neighbour *neigh = NULL;
1224         unsigned hash;
1225         int flags = 0;
1226         __le16 gateway = 0;
1227         __le16 local_src = 0;
1228         struct flowi fl = { .nl_u = { .dn_u =
1229                                      { .daddr = cb->dst,
1230                                        .saddr = cb->src,
1231                                        .scope = RT_SCOPE_UNIVERSE,
1232 #ifdef CONFIG_DECNET_ROUTE_FWMARK
1233                                        .fwmark = skb->nfmark
1234 #endif
1235                                     } },
1236                             .iif = skb->dev->ifindex };
1237         struct dn_fib_res res = { .fi = NULL, .type = RTN_UNREACHABLE };
1238         int err = -EINVAL;
1239         int free_res = 0;
1240
1241         dev_hold(in_dev);
1242
1243         if ((dn_db = in_dev->dn_ptr) == NULL)
1244                 goto out;
1245
1246         /* Zero source addresses are not allowed */
1247         if (fl.fld_src == 0)
1248                 goto out;
1249
1250         /*
1251          * In this case we've just received a packet from a source
1252          * outside ourselves pretending to come from us. We don't
1253          * allow it any further to prevent routing loops, spoofing and
1254          * other nasties. Loopback packets already have the dst attached
1255          * so this only affects packets which have originated elsewhere.
1256          */
1257         err  = -ENOTUNIQ;
1258         if (dn_dev_islocal(in_dev, cb->src))
1259                 goto out;
1260
1261         err = dn_fib_lookup(&fl, &res);
1262         if (err) {
1263                 if (err != -ESRCH)
1264                         goto out;
1265                 /*
1266                  * Is the destination us ?
1267                  */
1268                 if (!dn_dev_islocal(in_dev, cb->dst))
1269                         goto e_inval;
1270
1271                 res.type = RTN_LOCAL;
1272                 flags |= RTCF_DIRECTSRC;
1273         } else {
1274                 __le16 src_map = fl.fld_src;
1275                 free_res = 1;
1276
1277                 out_dev = DN_FIB_RES_DEV(res);
1278                 if (out_dev == NULL) {
1279                         if (net_ratelimit())
1280                                 printk(KERN_CRIT "Bug in dn_route_input_slow() "
1281                                                  "No output device\n");
1282                         goto e_inval;
1283                 }
1284                 dev_hold(out_dev);
1285
1286                 if (res.r)
1287                         src_map = dn_fib_rules_policy(fl.fld_src, &res, &flags);
1288
1289                 gateway = DN_FIB_RES_GW(res);
1290                 if (res.type == RTN_NAT) {
1291                         fl.fld_dst = dn_fib_rules_map_destination(fl.fld_dst, &res);
1292                         dn_fib_res_put(&res);
1293                         free_res = 0;
1294                         if (dn_fib_lookup(&fl, &res))
1295                                 goto e_inval;
1296                         free_res = 1;
1297                         if (res.type != RTN_UNICAST)
1298                                 goto e_inval;
1299                         flags |= RTCF_DNAT;
1300                         gateway = fl.fld_dst;
1301                 }
1302                 fl.fld_src = src_map;
1303         }
1304
1305         switch(res.type) {
1306         case RTN_UNICAST:
1307                 /*
1308                  * Forwarding check here, we only check for forwarding
1309                  * being turned off, if you want to only forward intra
1310                  * area, its up to you to set the routing tables up
1311                  * correctly.
1312                  */
1313                 if (dn_db->parms.forwarding == 0)
1314                         goto e_inval;
1315
1316                 if (res.fi->fib_nhs > 1 && fl.oif == 0)
1317                         dn_fib_select_multipath(&fl, &res);
1318
1319                 /*
1320                  * Check for out_dev == in_dev. We use the RTCF_DOREDIRECT
1321                  * flag as a hint to set the intra-ethernet bit when
1322                  * forwarding. If we've got NAT in operation, we don't do
1323                  * this optimisation.
1324                  */
1325                 if (out_dev == in_dev && !(flags & RTCF_NAT))
1326                         flags |= RTCF_DOREDIRECT;
1327
1328                 local_src = DN_FIB_RES_PREFSRC(res);
1329
1330         case RTN_BLACKHOLE:
1331         case RTN_UNREACHABLE:
1332                 break;
1333         case RTN_LOCAL:
1334                 flags |= RTCF_LOCAL;
1335                 fl.fld_src = cb->dst;
1336                 fl.fld_dst = cb->src;
1337
1338                 /* Routing tables gave us a gateway */
1339                 if (gateway)
1340                         goto make_route;
1341
1342                 /* Packet was intra-ethernet, so we know its on-link */
1343                 if (cb->rt_flags | DN_RT_F_IE) {
1344                         gateway = cb->src;
1345                         flags |= RTCF_DIRECTSRC;
1346                         goto make_route;
1347                 }
1348
1349                 /* Use the default router if there is one */
1350                 neigh = neigh_clone(dn_db->router);
1351                 if (neigh) {
1352                         gateway = ((struct dn_neigh *)neigh)->addr;
1353                         goto make_route;
1354                 }
1355
1356                 /* Close eyes and pray */
1357                 gateway = cb->src;
1358                 flags |= RTCF_DIRECTSRC;
1359                 goto make_route;
1360         default:
1361                 goto e_inval;
1362         }
1363
1364 make_route:
1365         rt = dst_alloc(&dn_dst_ops);
1366         if (rt == NULL)
1367                 goto e_nobufs;
1368
1369         rt->rt_saddr      = fl.fld_src;
1370         rt->rt_daddr      = fl.fld_dst;
1371         rt->rt_gateway    = fl.fld_dst;
1372         if (gateway)
1373                 rt->rt_gateway = gateway;
1374         rt->rt_local_src  = local_src ? local_src : rt->rt_saddr;
1375
1376         rt->rt_dst_map    = fl.fld_dst;
1377         rt->rt_src_map    = fl.fld_src;
1378
1379         rt->fl.fld_src    = cb->src;
1380         rt->fl.fld_dst    = cb->dst;
1381         rt->fl.oif        = 0;
1382         rt->fl.iif        = in_dev->ifindex;
1383         rt->fl.fld_fwmark = fl.fld_fwmark;
1384
1385         rt->u.dst.flags = DST_HOST;
1386         rt->u.dst.neighbour = neigh;
1387         rt->u.dst.dev = out_dev;
1388         rt->u.dst.lastuse = jiffies;
1389         rt->u.dst.output = dn_rt_bug;
1390         switch(res.type) {
1391                 case RTN_UNICAST:
1392                         rt->u.dst.input = dn_forward;
1393                         break;
1394                 case RTN_LOCAL:
1395                         rt->u.dst.output = dn_output;
1396                         rt->u.dst.input = dn_nsp_rx;
1397                         rt->u.dst.dev = in_dev;
1398                         flags |= RTCF_LOCAL;
1399                         break;
1400                 default:
1401                 case RTN_UNREACHABLE:
1402                 case RTN_BLACKHOLE:
1403                         rt->u.dst.input = dn_blackhole;
1404         }
1405         rt->rt_flags = flags;
1406         if (rt->u.dst.dev)
1407                 dev_hold(rt->u.dst.dev);
1408
1409         err = dn_rt_set_next_hop(rt, &res);
1410         if (err)
1411                 goto e_neighbour;
1412
1413         hash = dn_hash(rt->fl.fld_src, rt->fl.fld_dst);
1414         dn_insert_route(rt, hash, (struct dn_route **)&skb->dst);
1415
1416 done:
1417         if (neigh)
1418                 neigh_release(neigh);
1419         if (free_res)
1420                 dn_fib_res_put(&res);
1421         dev_put(in_dev);
1422         if (out_dev)
1423                 dev_put(out_dev);
1424 out:
1425         return err;
1426
1427 e_inval:
1428         err = -EINVAL;
1429         goto done;
1430
1431 e_nobufs:
1432         err = -ENOBUFS;
1433         goto done;
1434
1435 e_neighbour:
1436         dst_free(&rt->u.dst);
1437         goto done;
1438 }
1439
1440 int dn_route_input(struct sk_buff *skb)
1441 {
1442         struct dn_route *rt;
1443         struct dn_skb_cb *cb = DN_SKB_CB(skb);
1444         unsigned hash = dn_hash(cb->src, cb->dst);
1445
1446         if (skb->dst)
1447                 return 0;
1448
1449         rcu_read_lock();
1450         for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt != NULL;
1451             rt = rcu_dereference(rt->u.rt_next)) {
1452                 if ((rt->fl.fld_src == cb->src) &&
1453                     (rt->fl.fld_dst == cb->dst) &&
1454                     (rt->fl.oif == 0) &&
1455 #ifdef CONFIG_DECNET_ROUTE_FWMARK
1456                     (rt->fl.fld_fwmark == skb->nfmark) &&
1457 #endif
1458                     (rt->fl.iif == cb->iif)) {
1459                         rt->u.dst.lastuse = jiffies;
1460                         dst_hold(&rt->u.dst);
1461                         rt->u.dst.__use++;
1462                         rcu_read_unlock();
1463                         skb->dst = (struct dst_entry *)rt;
1464                         return 0;
1465                 }
1466         }
1467         rcu_read_unlock();
1468
1469         return dn_route_input_slow(skb);
1470 }
1471
1472 static int dn_rt_fill_info(struct sk_buff *skb, u32 pid, u32 seq,
1473                            int event, int nowait, unsigned int flags)
1474 {
1475         struct dn_route *rt = (struct dn_route *)skb->dst;
1476         struct rtmsg *r;
1477         struct nlmsghdr *nlh;
1478         unsigned char *b = skb->tail;
1479         struct rta_cacheinfo ci;
1480
1481         nlh = NLMSG_NEW(skb, pid, seq, event, sizeof(*r), flags);
1482         r = NLMSG_DATA(nlh);
1483         r->rtm_family = AF_DECnet;
1484         r->rtm_dst_len = 16;
1485         r->rtm_src_len = 0;
1486         r->rtm_tos = 0;
1487         r->rtm_table = RT_TABLE_MAIN;
1488         r->rtm_type = rt->rt_type;
1489         r->rtm_flags = (rt->rt_flags & ~0xFFFF) | RTM_F_CLONED;
1490         r->rtm_scope = RT_SCOPE_UNIVERSE;
1491         r->rtm_protocol = RTPROT_UNSPEC;
1492         if (rt->rt_flags & RTCF_NOTIFY)
1493                 r->rtm_flags |= RTM_F_NOTIFY;
1494         RTA_PUT(skb, RTA_DST, 2, &rt->rt_daddr);
1495         if (rt->fl.fld_src) {
1496                 r->rtm_src_len = 16;
1497                 RTA_PUT(skb, RTA_SRC, 2, &rt->fl.fld_src);
1498         }
1499         if (rt->u.dst.dev)
1500                 RTA_PUT(skb, RTA_OIF, sizeof(int), &rt->u.dst.dev->ifindex);
1501         /*
1502          * Note to self - change this if input routes reverse direction when
1503          * they deal only with inputs and not with replies like they do
1504          * currently.
1505          */
1506         RTA_PUT(skb, RTA_PREFSRC, 2, &rt->rt_local_src);
1507         if (rt->rt_daddr != rt->rt_gateway)
1508                 RTA_PUT(skb, RTA_GATEWAY, 2, &rt->rt_gateway);
1509         if (rtnetlink_put_metrics(skb, rt->u.dst.metrics) < 0)
1510                 goto rtattr_failure;
1511         ci.rta_lastuse = jiffies_to_clock_t(jiffies - rt->u.dst.lastuse);
1512         ci.rta_used     = rt->u.dst.__use;
1513         ci.rta_clntref  = atomic_read(&rt->u.dst.__refcnt);
1514         if (rt->u.dst.expires)
1515                 ci.rta_expires = jiffies_to_clock_t(rt->u.dst.expires - jiffies);
1516         else
1517                 ci.rta_expires = 0;
1518         ci.rta_error    = rt->u.dst.error;
1519         ci.rta_id       = ci.rta_ts = ci.rta_tsage = 0;
1520         RTA_PUT(skb, RTA_CACHEINFO, sizeof(ci), &ci);
1521         if (rt->fl.iif)
1522                 RTA_PUT(skb, RTA_IIF, sizeof(int), &rt->fl.iif);
1523
1524         nlh->nlmsg_len = skb->tail - b;
1525         return skb->len;
1526
1527 nlmsg_failure:
1528 rtattr_failure:
1529         skb_trim(skb, b - skb->data);
1530         return -1;
1531 }
1532
1533 /*
1534  * This is called by both endnodes and routers now.
1535  */
1536 int dn_cache_getroute(struct sk_buff *in_skb, struct nlmsghdr *nlh, void *arg)
1537 {
1538         struct rtattr **rta = arg;
1539         struct rtmsg *rtm = NLMSG_DATA(nlh);
1540         struct dn_route *rt = NULL;
1541         struct dn_skb_cb *cb;
1542         int err;
1543         struct sk_buff *skb;
1544         struct flowi fl;
1545
1546         memset(&fl, 0, sizeof(fl));
1547         fl.proto = DNPROTO_NSP;
1548
1549         skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL);
1550         if (skb == NULL)
1551                 return -ENOBUFS;
1552         skb->mac.raw = skb->data;
1553         cb = DN_SKB_CB(skb);
1554
1555         if (rta[RTA_SRC-1])
1556                 memcpy(&fl.fld_src, RTA_DATA(rta[RTA_SRC-1]), 2);
1557         if (rta[RTA_DST-1])
1558                 memcpy(&fl.fld_dst, RTA_DATA(rta[RTA_DST-1]), 2);
1559         if (rta[RTA_IIF-1])
1560                 memcpy(&fl.iif, RTA_DATA(rta[RTA_IIF-1]), sizeof(int));
1561
1562         if (fl.iif) {
1563                 struct net_device *dev;
1564                 if ((dev = dev_get_by_index(fl.iif)) == NULL) {
1565                         kfree_skb(skb);
1566                         return -ENODEV;
1567                 }
1568                 if (!dev->dn_ptr) {
1569                         dev_put(dev);
1570                         kfree_skb(skb);
1571                         return -ENODEV;
1572                 }
1573                 skb->protocol = __constant_htons(ETH_P_DNA_RT);
1574                 skb->dev = dev;
1575                 cb->src = fl.fld_src;
1576                 cb->dst = fl.fld_dst;
1577                 local_bh_disable();
1578                 err = dn_route_input(skb);
1579                 local_bh_enable();
1580                 memset(cb, 0, sizeof(struct dn_skb_cb));
1581                 rt = (struct dn_route *)skb->dst;
1582                 if (!err && -rt->u.dst.error)
1583                         err = rt->u.dst.error;
1584         } else {
1585                 int oif = 0;
1586                 if (rta[RTA_OIF - 1])
1587                         memcpy(&oif, RTA_DATA(rta[RTA_OIF - 1]), sizeof(int));
1588                 fl.oif = oif;
1589                 err = dn_route_output_key((struct dst_entry **)&rt, &fl, 0);
1590         }
1591
1592         if (skb->dev)
1593                 dev_put(skb->dev);
1594         skb->dev = NULL;
1595         if (err)
1596                 goto out_free;
1597         skb->dst = &rt->u.dst;
1598         if (rtm->rtm_flags & RTM_F_NOTIFY)
1599                 rt->rt_flags |= RTCF_NOTIFY;
1600
1601         NETLINK_CB(skb).dst_pid = NETLINK_CB(in_skb).pid;
1602
1603         err = dn_rt_fill_info(skb, NETLINK_CB(in_skb).pid, nlh->nlmsg_seq, RTM_NEWROUTE, 0, 0);
1604
1605         if (err == 0)
1606                 goto out_free;
1607         if (err < 0) {
1608                 err = -EMSGSIZE;
1609                 goto out_free;
1610         }
1611
1612         err = netlink_unicast(rtnl, skb, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
1613
1614         return err;
1615
1616 out_free:
1617         kfree_skb(skb);
1618         return err;
1619 }
1620
1621 /*
1622  * For routers, this is called from dn_fib_dump, but for endnodes its
1623  * called directly from the rtnetlink dispatch table.
1624  */
1625 int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb)
1626 {
1627         struct dn_route *rt;
1628         int h, s_h;
1629         int idx, s_idx;
1630
1631         if (NLMSG_PAYLOAD(cb->nlh, 0) < sizeof(struct rtmsg))
1632                 return -EINVAL;
1633         if (!(((struct rtmsg *)NLMSG_DATA(cb->nlh))->rtm_flags&RTM_F_CLONED))
1634                 return 0;
1635
1636         s_h = cb->args[0];
1637         s_idx = idx = cb->args[1];
1638         for(h = 0; h <= dn_rt_hash_mask; h++) {
1639                 if (h < s_h)
1640                         continue;
1641                 if (h > s_h)
1642                         s_idx = 0;
1643                 rcu_read_lock_bh();
1644                 for(rt = rcu_dereference(dn_rt_hash_table[h].chain), idx = 0;
1645                         rt;
1646                         rt = rcu_dereference(rt->u.rt_next), idx++) {
1647                         if (idx < s_idx)
1648                                 continue;
1649                         skb->dst = dst_clone(&rt->u.dst);
1650                         if (dn_rt_fill_info(skb, NETLINK_CB(cb->skb).pid,
1651                                         cb->nlh->nlmsg_seq, RTM_NEWROUTE,
1652                                         1, NLM_F_MULTI) <= 0) {
1653                                 dst_release(xchg(&skb->dst, NULL));
1654                                 rcu_read_unlock_bh();
1655                                 goto done;
1656                         }
1657                         dst_release(xchg(&skb->dst, NULL));
1658                 }
1659                 rcu_read_unlock_bh();
1660         }
1661
1662 done:
1663         cb->args[0] = h;
1664         cb->args[1] = idx;
1665         return skb->len;
1666 }
1667
1668 #ifdef CONFIG_PROC_FS
1669 struct dn_rt_cache_iter_state {
1670         int bucket;
1671 };
1672
1673 static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq)
1674 {
1675         struct dn_route *rt = NULL;
1676         struct dn_rt_cache_iter_state *s = seq->private;
1677
1678         for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) {
1679                 rcu_read_lock_bh();
1680                 rt = dn_rt_hash_table[s->bucket].chain;
1681                 if (rt)
1682                         break;
1683                 rcu_read_unlock_bh();
1684         }
1685         return rt;
1686 }
1687
1688 static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt)
1689 {
1690         struct dn_rt_cache_iter_state *s = rcu_dereference(seq->private);
1691
1692         rt = rt->u.rt_next;
1693         while(!rt) {
1694                 rcu_read_unlock_bh();
1695                 if (--s->bucket < 0)
1696                         break;
1697                 rcu_read_lock_bh();
1698                 rt = dn_rt_hash_table[s->bucket].chain;
1699         }
1700         return rt;
1701 }
1702
1703 static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos)
1704 {
1705         struct dn_route *rt = dn_rt_cache_get_first(seq);
1706
1707         if (rt) {
1708                 while(*pos && (rt = dn_rt_cache_get_next(seq, rt)))
1709                         --*pos;
1710         }
1711         return *pos ? NULL : rt;
1712 }
1713
1714 static void *dn_rt_cache_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1715 {
1716         struct dn_route *rt = dn_rt_cache_get_next(seq, v);
1717         ++*pos;
1718         return rt;
1719 }
1720
1721 static void dn_rt_cache_seq_stop(struct seq_file *seq, void *v)
1722 {
1723         if (v)
1724                 rcu_read_unlock_bh();
1725 }
1726
1727 static int dn_rt_cache_seq_show(struct seq_file *seq, void *v)
1728 {
1729         struct dn_route *rt = v;
1730         char buf1[DN_ASCBUF_LEN], buf2[DN_ASCBUF_LEN];
1731
1732         seq_printf(seq, "%-8s %-7s %-7s %04d %04d %04d\n",
1733                         rt->u.dst.dev ? rt->u.dst.dev->name : "*",
1734                         dn_addr2asc(dn_ntohs(rt->rt_daddr), buf1),
1735                         dn_addr2asc(dn_ntohs(rt->rt_saddr), buf2),
1736                         atomic_read(&rt->u.dst.__refcnt),
1737                         rt->u.dst.__use,
1738                         (int) dst_metric(&rt->u.dst, RTAX_RTT));
1739         return 0;
1740 }
1741
1742 static struct seq_operations dn_rt_cache_seq_ops = {
1743         .start  = dn_rt_cache_seq_start,
1744         .next   = dn_rt_cache_seq_next,
1745         .stop   = dn_rt_cache_seq_stop,
1746         .show   = dn_rt_cache_seq_show,
1747 };
1748
1749 static int dn_rt_cache_seq_open(struct inode *inode, struct file *file)
1750 {
1751         struct seq_file *seq;
1752         int rc = -ENOMEM;
1753         struct dn_rt_cache_iter_state *s = kmalloc(sizeof(*s), GFP_KERNEL);
1754
1755         if (!s)
1756                 goto out;
1757         rc = seq_open(file, &dn_rt_cache_seq_ops);
1758         if (rc)
1759                 goto out_kfree;
1760         seq             = file->private_data;
1761         seq->private    = s;
1762         memset(s, 0, sizeof(*s));
1763 out:
1764         return rc;
1765 out_kfree:
1766         kfree(s);
1767         goto out;
1768 }
1769
1770 static struct file_operations dn_rt_cache_seq_fops = {
1771         .owner   = THIS_MODULE,
1772         .open    = dn_rt_cache_seq_open,
1773         .read    = seq_read,
1774         .llseek  = seq_lseek,
1775         .release = seq_release_private,
1776 };
1777
1778 #endif /* CONFIG_PROC_FS */
1779
1780 void __init dn_route_init(void)
1781 {
1782         int i, goal, order;
1783
1784         dn_dst_ops.kmem_cachep = kmem_cache_create("dn_dst_cache",
1785                                                    sizeof(struct dn_route),
1786                                                    0, SLAB_HWCACHE_ALIGN,
1787                                                    NULL, NULL);
1788
1789         if (!dn_dst_ops.kmem_cachep)
1790                 panic("DECnet: Failed to allocate dn_dst_cache\n");
1791
1792         init_timer(&dn_route_timer);
1793         dn_route_timer.function = dn_dst_check_expire;
1794         dn_route_timer.expires = jiffies + decnet_dst_gc_interval * HZ;
1795         add_timer(&dn_route_timer);
1796
1797         goal = num_physpages >> (26 - PAGE_SHIFT);
1798
1799         for(order = 0; (1UL << order) < goal; order++)
1800                 /* NOTHING */;
1801
1802         /*
1803          * Only want 1024 entries max, since the table is very, very unlikely
1804          * to be larger than that.
1805          */
1806         while(order && ((((1UL << order) * PAGE_SIZE) /
1807                                 sizeof(struct dn_rt_hash_bucket)) >= 2048))
1808                 order--;
1809
1810         do {
1811                 dn_rt_hash_mask = (1UL << order) * PAGE_SIZE /
1812                         sizeof(struct dn_rt_hash_bucket);
1813                 while(dn_rt_hash_mask & (dn_rt_hash_mask - 1))
1814                         dn_rt_hash_mask--;
1815                 dn_rt_hash_table = (struct dn_rt_hash_bucket *)
1816                         __get_free_pages(GFP_ATOMIC, order);
1817         } while (dn_rt_hash_table == NULL && --order > 0);
1818
1819         if (!dn_rt_hash_table)
1820                 panic("Failed to allocate DECnet route cache hash table\n");
1821
1822         printk(KERN_INFO
1823                 "DECnet: Routing cache hash table of %u buckets, %ldKbytes\n",
1824                 dn_rt_hash_mask,
1825                 (long)(dn_rt_hash_mask*sizeof(struct dn_rt_hash_bucket))/1024);
1826
1827         dn_rt_hash_mask--;
1828         for(i = 0; i <= dn_rt_hash_mask; i++) {
1829                 spin_lock_init(&dn_rt_hash_table[i].lock);
1830                 dn_rt_hash_table[i].chain = NULL;
1831         }
1832
1833         dn_dst_ops.gc_thresh = (dn_rt_hash_mask + 1);
1834
1835         proc_net_fops_create("decnet_cache", S_IRUGO, &dn_rt_cache_seq_fops);
1836 }
1837
1838 void __exit dn_route_cleanup(void)
1839 {
1840         del_timer(&dn_route_timer);
1841         dn_run_flush(0);
1842
1843         proc_net_remove("decnet_cache");
1844 }
1845